Obstruction lighting system configured to emit visible and infrared light

ABSTRACT

A lighting system includes a first light assembly that is configured to emit light periodically. The lighting system further includes a second light assembly that is spaced apart from the first light assembly, the second light assembly also being configured to emit light periodically. The periodic light emitted by the first and second light assemblies is synchronized such that the first and second light assemblies operate in unison to form a single light source.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/099,668, filed Apr. 15, 2016, which claims priority to U.S.provisional patent application No. 62/148,584, filed Apr. 16, 2015, theentire contents of each of these applications being expresslyincorporated by reference herein.

FIELD

The present disclosure relates generally to lighting systems, inparticular to obstruction lighting systems.

BACKGROUND

The Federal Aviation Administration (FAA) requires that obstructions toaircraft navigation, such as towers, cables and tall buildings be fittedwith visibly perceivable elements to render these structures highlyvisible to approaching aircraft. FAA Advisory Circular 150/5345-43 formsa specification of technical requirements for these lights in the UnitedStates. Within Advisory Circular 150/5345-43 there exists a requirementfor a medium-intensity flashing red obstruction light system, designatedthe “L-864” and a medium-intensity flashing white obstruction light,designated the “L-865.” These obstruction lights are to be placed inaccordance with a set plan at levels on all obstructions that arepotential hazards to air navigation.

For the L-864 obstruction light, at all radials throughout a 360 degreeazimuth, there must be a peak effective intensity of 2,000±25 percentcandela. There must also be a minimum effective intensity of 750 candelathroughout a minimum vertical beam spread of 3 degrees. For the L-865obstruction light, at all radials throughout a 360 degree azimuth, theremust be a peak effective intensity of 20,000±25 percent candela duringoperation at day and twilight conditions, and 2,000±25 percent candeladuring night conditions. The L-865 obstruction light also includes aminimum vertical beam spread of 3 degrees.

While visible-light obstruction lighting performance standards are wellestablished, there are no standards for compatibility of obstructionlights with night vision imaging systems (“NVIS”) commonly used bymilitary and emergency/rescue air operators. NVIS systems are typicallyconfigured to receive and amplify low-level infrared radiation to form a“night vision” image, which improves air operators' ability to navigateat night, especially in poor visibility conditions. The lack ofperformance standards for compatibility with NVIS systems isparticularly problematic for obstruction lights that utilize lightemitting diodes (LEDs), since LEDs generate considerably less heat (andthus less infrared radiation) than conventional incandescent and xenonstrobe light sources, making them difficult to see with NVIS. Providersof obstruction lighting systems have attempted to solve this problem byadding some infrared light emitting diodes (IRLEDs) to theirvisible-light obstruction lighting systems. However, since theseobstruction lighting systems are optimized to emit visible light theyare often poor emitters of infrared light. There remains a need for anobstruction lighting system that provides satisfactory light emissionsfor both visible light and infrared light.

SUMMARY

An obstruction lighting system configured to emit visible and infraredlight is disclosed. The system comprises a first light assembly that isconfigured to emit visible light. A second light assembly is configuredto emit infrared light. A mounting bracket couples together the secondlight assembly and the first light assembly.

According to one embodiment, a lighting system includes a first lightassembly that is configured to emit light periodically. The lightingsystem further includes a second light assembly that is spaced apartfrom the first light assembly, the second light assembly also beingconfigured to emit light periodically. The periodic light emitted by thefirst and second light assemblies is synchronized such that the firstand second light assemblies operate in unison to form a single lightsource.

In another embodiment a lighting system comprises a first light assemblythat is configured to emit light periodically. A second light assemblyis spaced apart from the first light assembly and is configured to emitlight periodically. The lighting system further includes a mountingbracket having a first, generally planar member and a second, generallytubular member attached to the first member and oriented generallyperpendicularly with respect to the first member. The second lightassembly is coupled to the second member. The periodic light emitted bythe first and second light assemblies is synchronized such that thefirst and second light assemblies operate in unison to form a singlelight source.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the inventive embodiments will become apparent tothose skilled in the art to which the embodiments relate from readingthe specification and claims with reference to the accompanyingdrawings, in which:

FIG. 1 shows the general arrangement of an obstruction lighting systemconfigured to emit both visible and infrared light;

FIG. 2 shows the general arrangement of a visible light assembly;

FIG. 3 shows the general arrangement of an infrared light assembly;

FIGS. 4 and 5 are top and side elevational views respectively showingdetails of a reflector of the infrared light assembly of FIG. 3;

FIGS. 6A, 6B and 6C show top plan, end elevational and side elevationalviews respectively of a mounting bracket of the system of FIG. 1;

FIG. 7 shows a controller and an alarm coupled to the system of FIG. 1;

FIG. 8 shows a synchronization control arrangement for the system ofFIG. 1;

FIG. 9 shows another synchronization control arrangement for the systemof FIG. 1; and

FIG. 10 shows yet another synchronization control arrangement for thesystem of FIG. 1.

DETAILED DESCRIPTION

The general arrangement of an obstruction lighting system 10 configuredto emit both visible and infrared light is shown in FIG. 1. System 10comprises a first light assembly 12 that is configured to emit visiblelight. A second light assembly 14 is configured to emit infrared light.

A mounting bracket 16 couples second light assembly 14 to a mountingbase 15 of first light assembly 12 and also provides a mounting pointfor the second light assembly that positions the second light assemblywith respect to the first light assembly.

Details of an example first light assembly 12 are shown in FIG. 2.Visible light 18 generated by a set of visible-light LEDs 20 isreflected by a reflector 22. The visible light 18 may be white or red incolor, and may be steady-burning or may flash at a predeterminedflashrate and ON-OFF duty cycle. First light assembly 12 may include atleast some of the features of U.S. Pat. No. 9,010,969, which is commonlyowned by the present applicant and is expressly incorporated byreference herein. First light assembly 12 may optionally be an FAA-typeL-864. LEDs 20 may vary in number, type, size, shape, style,orientation, arrangement, and so on to suit a particular application.Likewise, the optical characteristics of first light assembly 12 mayalso be varied, such as with various types, sizes, shapes, styles,orientations, arrangements, and so on of reflectors and lenses to suit aparticular application.

Details of an example second light assembly 14 are shown in FIG. 3.Second light assembly 14 may optionally be an FAA-type L-810. Infraredlight 24 generated by a set of IRLEDs 26 is reflected by a reflector 28.Further details of reflector 28 are shown in FIGS. 4 and 5. In someembodiments one or more light-reflecting surfaces of reflector 28 may becoated with materials such as, but not limited to, gold. IRLEDs 26 mayvary in number, type, size, shape, style, orientation, arrangement, andso on to suit a particular application. Likewise, the opticalcharacteristics of second light assembly 14 may also be varied, such aswith various quantities, types, sizes, shapes, styles, orientations,arrangements, and so on of reflectors and lenses to suit a particularapplication.

The infrared light 24 may be steady-burning or may flash at apredetermined flashrate and ON-OFF duty cycle. Second light assembly 14may include at least some of the features of U.S. Pat. No. 9,016,896,which is commonly owned by the present applicant and is expresslyincorporated by reference herein.

In some embodiments thermal management of IRLEDs 26 is applied such thatheat is spread generally evenly to a supporting metal heat sink 30 thatis in thermal communication with the IRLEDs. Preferably, driverelectronics 32 for powering IRLEDs 26 are thermally isolated from theIRLEDs, such as being located under the IRLEDs within a housing 33 orremotely located so the driver electronics do not gain heat from theIRLEDs. A similar arrangement may be utilized for visible-light LEDs 20.

With reference to FIGS. 6A, 6B and 6C, mounting bracket 16 includes agenerally U-shaped first portion 34, which is coupled to mounting base15 of first lighting assembly 12. A second portion 36 is orientedgenerally perpendicularly with respect to first portion 34. Secondlighting assembly 14 is attached to a distal end 38 of second portion36. In one embodiment second portion 36 is made selectably adjustablewith respect to first portion 34, to allow vertical adjustment of theposition of second lighting assembly 14.

Mounting bracket 16 may be made from any suitable materials including,without limitation, steel, stainless steel, titanium, aluminum,composite and polymer materials and may be formed using any suitableprocesses including, without limitation, casting, machining, spinning,stamping, forming, molding and forging. Surfaces of the components ofmounting bracket 16 may be prepared and treated in any suitable manner,or may be left unfinished. Non-limiting example treatments include anyof painting, plastic coating, powder coating, hot-dip galvanizing,plating, dyes, polishing, and molded-in colors. In addition, at leastsome of the various components of mounting bracket 16 may be formed asan assembly of separate components and joined together, or may be madeas a single unitary piece. The components of mounting bracket 16 may beheat treated and/or shot peened as appropriate for the materialsselected for the components of the mounting bracket.

With reference again to FIG. 1 in combination with FIGS. 6A, 6B, 6C and7, second light assembly 14 and mounting bracket 16 are preferably sizedand shaped so that they adequately support the second light assemblywhile blocking only a minimal part of the visible light 18 emitted byfirst light assembly 12. Mounting bracket 16 and second lightingassembly 14 are also preferably relatively small in size to presentminimal additional wind loading to an obstruction (e.g., a tower) towhich system 10 is mounted.

Mounting bracket 16 is preferably configured such that it can beinstalled without complete removal of mounting hardware 40 (FIG. 7) usedto selectably couple the mounting base 15 of first light assembly 12 toa support member 42 of an obstruction (not shown) to which system 10 isattached. To install mounting bracket 16, mounting hardware 40 isloosened sufficiently to allow one or more arms 44 (FIG. 6B) of firstportion 34 to fit between mounting base 15 of first light assembly 12and support member 42. An opening 46 of one or more generally L-shapedapertures 48 of each arm 44 is aligned with corresponding mountinghardware 40. Mounting bracket 16 is moved in a first direction “A” suchthat the mounting hardware 40 moves into a first aperture portion 50.Mounting bracket 16 is then moved in a second direction “B” such thatthe mounting hardware 40 moves into a second aperture portion 52.Mounting hardware 40 is then re-tightened, securing together mountingbracket 16, first light assembly 12 and support member 42. This processmay be carried out in reverse to uninstall bracket 16.

Mounting bracket 16 is preferably further configured to allow electricalwiring (not shown) for second light assembly 14 to pass through secondbracket portion 36 without obstructing the visible light output fromfirst light assembly 12.

As previously noted, first light assembly 12 and/or second lightassembly 14 may be configured to be steady-burning or to flash at one ormore predetermined flashrate and/or duty cycles. In one embodiment firstlight assembly 12 and second light assembly 14 flash independently ofone another. In another embodiment the flashing of first light assembly12 and second light assembly 14 may be controlled by a controller 54,shown in FIG. 7. Controller 54 may be configured to flash first lightassembly 12 and second light assembly 14 in a predetermined manner, suchas synchronously together or alternately. Alternatively, controller 54may be configured to synchronize flash control circuitry (not shown)disposed in first light assembly 12 and/or second light assembly 14.Controller 54 may be a separate component of system 10, or may beincorporated into either or both of first light assembly 12 and secondlight assembly 14, in whole or in part.

In some embodiments controller 54 may monitor first light assembly 12and/or second light assembly 14 for faults including, but not limitedto, failures of LEDs 20 and IRLEDs 26. Example failures include, withoutlimitation, an open-circuit and a short-circuit condition in the lightemitting diodes. Upon detection of faults controller 54 may activate oneor more alarms 56, which may be local and/or remote to system 10, thealarm providing an alerting signal to alert service personnel of thefaults.

Alarm 56 may be a separate component, or may be partially or fullycombined with controller 54. Alternatively, alarm 56 may be partially orfully incorporated into either or both of first light assembly 12 andsecond light assembly 14, with or without portions or all of controller54.

With reference to FIG. 8, in yet another embodiment a light sensor 58 iscoupled to controller 54 and provides an electrical synchronizationsignal 60 to the controller when the light sensor detects visible light18 emitted by first light assembly 12. Controller 54 in turn provides anON-OFF signal 62 to an LED driver power supply 64 to selectably activateIRLEDs 26 of second light assembly 14 synchronously with thevisible-light LEDs 20 of first light assembly 12. Preferably, IRLEDs 26turn on at substantially the same time as visible-light LEDs 20 and alsoturn off at substantially the same time as visible-light LEDs. In thisway, the first and second light assemblies 12, 14 respectively operatein unison to form a single light source that emits both visible andinfrared light without the need to provide an electrical synchronizationsignal to both the first and second light assemblies. In effect, thelight output of second light assembly 14 is optically “slaved” to thelight output of first light assembly 12.

Light sensor 58 may be any suitable type of light sensor positioned toreceive light emitted by visible-light LEDs 20. Examples include,without limitation, variable-resistance photocells such as cadmiumsulfide photocells, photo-transistors, and photo-diodes.

A light discriminator 66 may be coupled to controller 54 to evaluatesynchronization signal 60 and enable the controller to ignore thesynchronization signal. As a non-limiting example, light discriminator66 may monitor for invalid or unchanging-state synchronization signals60 and enable controller 54 via a light discriminator signal 68 toignore the synchronization signal. In one embodiment light discriminator66 is configured to deter an LED driver 64 from turning on IRLEDs 26during daylight hours.

In still another embodiment, shown in FIG. 9, a first light assembly 12and a second light assembly 14 are provided an electricalsynchronization signal 70 by controller 54. In this arrangement thetiming of first light assembly 12 and second light assembly 14 are bothslaved to controller 54. Controller 54 may also be configured to controlthe flashrate and ON-OFF duty cycle of either or both of first lightassembly 12 and second light assembly 14.

In still another embodiment, shown in FIG. 10, first light assembly 12provides second light assembly 14 an electrical synchronization signal72. In this arrangement the flashrate and ON-OFF duty cycle of secondlight assembly 14 is slaved to that of first light assembly 12. Althoughnot shown in the Figures, it will be appreciated that an arrangementwherein first light assembly 12 is similarly slaved to second lightassembly 14 is within the scope of the present disclosure.

Although controller 54 is shown as a separate component in the severalFigures, it will be appreciated that the control may be made part ofeither first light assembly 12 or second light assembly 14.Alternatively, portions of controller 54 may be incorporated into any orall of first light assembly 12, second light assembly 14 and an assemblyor assemblies that are separate from the first and second lightassemblies. In still other embodiments synchronization signals may begenerated by either or both first light assembly 12 and second lightassembly 14 and supplied directly to the other without a controller.

While this invention has been shown and described with respect to adetailed embodiment thereof, it will be understood by those skilled inthe art that changes in form and detail thereof may be made withoutdeparting from the scope of the claims of the invention.

What is claimed is:
 1. A lighting system, comprising: a first lightassembly configured to emit light periodically at a predeterminedflashrate; a second light assembly spaced apart from the first lightassembly, the second light assembly being configured to emit lightperiodically; a light sensor configured to detect light emitted by thefirst light assembly; and a controller coupled to the light sensor, thecontroller controlling the periodic light emissions of the second lightassembly such that the light emissions of the second light assembly areslaved to the light emissions of the first light assembly, the lightemissions of the second light assembly turning on and off atsubstantially the same times as the light emissions of the first lightassembly, the first and second light assemblies operating in unison toform a single light source.
 2. The lighting system of claim 1, furtherincluding a mounting bracket having a first and a second, opposing endextending between the first and the second light assemblies.
 3. Thelighting system of claim 2 wherein: the first light assembly furtherincludes a mounting base; the first end of the mounting bracket iscoupled to the mounting base; and the second light assembly is attachedto the second end of the mounting bracket.
 4. The lighting system ofclaim 3, further comprising: mounting hardware to selectably couple themounting base to the first end of the mounting bracket; and at least onegenerally “L”-shaped aperture formed in the first end of the mountingbracket, the aperture being configured to receive the mounting hardwarewithout removal of said mounting hardware from the mounting base.
 5. Thelighting system of claim 2 wherein the mounting bracket comprises: agenerally planar first member; and a generally tubular second memberattached to the first member and oriented generally perpendicularly withrespect to the first member.
 6. The lighting system of claim 5 whereinthe second member is adjustably attached to the first member.
 7. Thelighting system of claim 1 wherein: the first light assembly emitsvisible light; and the second light assembly emits infrared light. 8.The lighting system of claim 7, wherein: the second light assemblyfurther includes a reflector having a light-reflecting surface; and thelight-reflecting surface of the reflector is coated with gold.
 9. Thelighting system of claim 1, further including a light discriminatorconfigured to disable the second light assembly during daylight hours.10. The lighting system of claim 1 wherein at least one of the first andsecond light assemblies comprises light emitting diodes.
 11. Thelighting system of claim 10, further including driver electronics tooperate the light emitting diodes, the driver electronics being spacedapart from the light emitting diodes, thereby thermally isolating thedriver electronics from the light emitting diodes.
 12. The lightingsystem of claim 1, further including an alarm configured to provide analerting signal upon detection of a fault in at least one of the firstand second light assemblies.
 13. The lighting system of claim 12 whereinthe second light assembly comprises light emitting diodes, the alarmbeing configured to detect at least one of an open-circuit and ashort-circuit condition in the light emitting diodes.
 14. A lightingsystem, comprising: a first light assembly configured to emit lightperiodically at a predetermined flashrate; a second light assemblyspaced apart from the first light assembly, the second light assemblybeing configured to emit light periodically; a mounting bracket having agenerally planar first member and a generally tubular second memberattached to the first member and oriented generally perpendicularly withrespect to the first member, the second light assembly being coupled tothe second member; a light sensor configured to detect light emitted bythe first light assembly; and a controller coupled to the light sensor,the controller controlling the periodic light emissions of the secondlight assembly such that the light emissions of the second lightassembly are slaved to the light emissions of the first light assembly,the light emissions of the second light assembly turning on and off atsubstantially the same times as the light emissions of the first lightassembly, the first and second light assemblies operating in unison toform a single light source.
 15. A method for providing lighting,comprising the steps of: configuring a first light assembly to emitlight periodically at a predetermined flashrate; spacing a second lightassembly apart from the first light assembly; configuring the secondlight assembly to emit light periodically; configuring a light sensor todetect light emitted by the first light assembly; and coupling acontroller to the light sensor, the controller controlling the periodiclight emissions of the second light assembly such that the lightemissions of the second light assembly are slaved to the light emissionsof the first light assembly, the light emissions of the second lightassembly turning on and off at substantially the same times as the lightemissions of the first light assembly, the first and second lightassemblies operating in unison to form a single light source.